AmpC beta lactamase producing Gram-negative bacteria have emerged worldwide. It is important to distinguish plasmid mediated AmpC β lactamases from chromosomally mediated enzymes for surveillance, epidemiology and hospital infection control as plasmid mediated genes can spread to other organisms. Occurrence of blaCMY-1 AmpC β-lactamase, a plasmid mediated cephamycinase was studied in 100 consec...

OBJECTIVES To characterize the naturally occurring β-lactamase gene identified from a clinical isolate belonging to a novel enterobacterial species that is closely related to Rahnella spp. and Ewingella spp. METHODS Shotgun cloning and expression in Escherichia coli were performed in order to characterize this resistance determinant. Enzymatic activities were measured by UV spectrophotometry ...

One of the leading sources of false positives in early drug discovery is the formation of organic small molecule aggregates, which inhibit enzymes nonspecifically at micromolar concentrations in aqueous solution. The molecular basis for this widespread problem remains hazy. To investigate the mechanism of inhibition at a molecular level, we determined changes in solvent accessibility that occur...

The exoceilular f-lactamase of Streptomyces albus G has been purified to near protein homogeneity. It consists of one single polypeptide chain of mol.wt. 30000-31000, has a rather low isoelectric point (at pH 6.0) and contains less lysine (2.1%) and more half-cystine residues than most fi-lactamases from other Gram-positive bacteria. Penicillins are much better substrates than A3-cephalosporins...

Two strains of Enterobacteriaceae producing prodigiosin were isolated from meat in the Sichuan province of China in 2010. The strains were identified by Vitek system, 16S rDNA, rpoB, pfs and luxS genes. Minimum inhibitory concentrations were determined using the broth microdilution method. The two strains were screened for the presence of β-lactamase genes (blaTEM, blaSHV, blaOKP, and blaCTX-M ...

OBJECTIVES To identify β-lactamase genes in gut commensal Bacteroides species and to assess the impact of these enzymes, when carried by outer membrane vesicles (OMVs), in protecting enteric pathogens and commensals. METHODS A deletion mutant of the putative class A β-lactamase gene (locus tag BT_4507) found in the genome of the human commensal Bacteroides thetaiotaomicron was constructed and...

In Gram-negative bacteria, TEM-1 beta-lactamase provides the major mechanism of plasmid-mediated beta-lactam resistance. Natural variants of TEM-1 with increased antibiotic resistance have appeared in response to the use of extended-spectrum beta-lactam antibiotics (e.g., ceftazidime) and beta-lactamase inhibitors (e.g., clavulanic acid). Some of the variant enzymes are more efficient at cataly...

Abstract Residues of antibiotics in water resources and wastewater have been significant environmental public health problems. The current study developed a high-efficiency enzymatic nanobiocatalyst for the degradation beta-lactam antibiotics. For this purpose, metallo-beta-lactamase IMP-1 was obtained by cloned blaIMP gene overexpressed Escherichia coli. 2.6 mg purified enzyme used immobilizat...

Pseudomonas aeruginosa (P. aeruginosa) places among major opportunistic nosocomial pathogen which has developed extensive drug resistance. Due to uncontrolled consumption of antibiotics, multidrug-resistant (MDR) P. species are increasingly isolated from various settings hospitals globally. This research aimed determine the genes reproducing blaOXA-48, blaIMP-1, blaVIM-1 and blaNDM-1 metallo be...

OBJECTIVES Indirect resistance (IR), the ability of an antibiotic-resistant population of bacteria to protect a susceptible population, has been previously observed for β-lactamase-producing bacteria and associated with antimicrobial treatment failures. Here, we determined whether other resistance determinants could cause IR in the presence of five other classes of antibiotics. METHODS A test...